On Wednesday, 14 December 2022 at 11:30:07 UTC, Vitaliy Fadeev
wrote:
Hi! I open a device under Windows:
```
HANDLE h = CreateFileW( ... );
```
in procedure:
```
HANDLE open_keyboard_device2( LPCWSTR path, int* error_number )
{
...
HANDLE dev_handle =
CreateFileW(
path,
0,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
0,
NULL
);
...
return dev_handle;
}
```
and I want to close HANDLE automatically, when **dev_handle**
destroyed by GC:
```
CloseHandle( h );
```
How to do it?
How to define HANDLE var ? What to return from procedure? How
to call CloseHandle( h ) when variable destroyed?
I was trying **std.typecons.Unique**. But where I must put
**CloseHandle( h )** ?
I was trying **std.typecons.Unique** with custom class
**SafeHabdle**
```
class SafeHandle
{
HANDLE h;
this( HANDLE h )
{
this.h = h;
}
~this()
{
if ( h != INVALID_HANDLE_VALUE )
CloseHandle( h );
}
}
```
and using it:
```
Unique!SafeHandle open_keyboard_device2( LPCWSTR path, int*
error_number )
{
...
Unique!SafeHandle dev_handle =
new SafeHandle(
CreateFileW(
path,
0,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
0,
NULL
)
);
...
}
```
It complex. Because needed:
```
Unique!SafeHandle open_keyboard_device2( LPCWSTR path, int*
error_number )
Unique!SafeHandle dev_handle = new SafeHandle( CreateFileW(
... ) );
DeviceIoControl( dev_handle.h, ...);
```
vs
```
HANDLE open_keyboard_device2( LPCWSTR path, int*
error_number )
HANDLE dev_handle = CreateFileW( ... );
DeviceIoControl( dev_handle, ...);
```
Last is readable.
Teach me the most beautiful way.
How to make beautiful?
Thanks!
If you need an specific shutdown maybe you can use scopes. But
I'm here learning too.
https://tour.dlang.org/tour/en/gems/scope-guards
